Anti-theft device



FIG. 1 is a top right side perspective view of an anti-theft device according to my new design,

FIG. 2 is a front view (the rear view is a mirror image),

FIG. 3 is a right side view,

FIG. 4 is a left side view,

FIG. 5 is a top view; and,

FIG. 6 is a bottom view. 

The ornamental design for an anti-theft device, as shown. 